@Feryll - I agree with you about the bird feeder offering an easy meal for some animals who eat the birds that come after the birdseed. I have never seen a hawk at my feeders, but I eventually took down all of my feeders because the neighborhood cats were always stalking the birds and snatching one when they got a chance.
I felt like I was setting the bait for the poor little birds and aiding the cats in their efforts to rid the neighborhood of birds. I have put bells on the collars of my cats in case they find go bird hunting this gives the birds a fighting chance. However, you might be surprised how quickly a cat will adapt and learn how to keep the bell almost silent.